Carbureter



A. M. PRENTISS.

CARBURETER. APPLICATION FlLED MAR. 6. 191.7.

1,329,309, Patented Jan. 27,1920.

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A. M. PRENTISS.

CARBURETER.

APPLICATION FILED MAR. 6, 1917.

Patented Jan. 27, 1920.

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i UNITED STATES. PATENT OFFICE.

AUGUSTIN M. PRENTISS, OF ROCK ISLAND, ILLINOS, ASSIGNOR OF ONE-HALE1 '1'0 DOUGLSS E. BULLOCI'I, OF WASHINGTON, DISTBICT OF COLUMBIA.

CARBURETER.

specification of Letters Patent.

Patented Jan. 27, 1920.

Application filed March 6, 1917. Serial No. 152.708.

To all whom z't may' concern Be it known that I, AUGUs'rIN M. IfnnN- Tiss, a citizen of the United States, reslding at Rock Island, in the county of Rock Island with the demands of the engine.

i of this kind wherein the pressure on the liquid fuel is at maximum vwhenthe englne' Third: To provide an'improved apparatus islat zero'speed and is'gradually diminished w as the speed' of. fthe engine increases `,until .fit reaches a value'equal toatmospheric when the'engine is at highest rated speed.

Fourth: To provide a device wherein the ratio. by weight, of liquid fuel to air is constantly maintalned'at a redetermined value throughout all of the c angesof speed of the engine.

Fifth: To provide a devicel which will furnish an ideal mixture at low speed, either onfull 'open or nearly closed throttle, tol

prevent the common tendency of motors to stall.

' Sixth: To provide an improved appara'tus of this nature having means for supplying air under pressure to the liquid fuel column within the fuel nozzle to break up the liquid column before it issues from the fuel nozzle and thus secure anatomizing efl'ect regardless of the variations of specific gravity in the liquid fuel.

The invention, with other objects and advantages thereof and` the particular construction, combination and arrangement of parts comprising the same,will be under- 'stood from the followingvdescription :when

considered in connection with the accompanying drawings forming a part hereof and wherein I have illustrated oneembodiment of the invention- In the drawings:

Figure 1 is a central Vertical section of a device constructed in 'accordance with the present invention. i

Fig. 2 is a section on the line 2-2 of Fig. 1.

Fig. 3 'is a section on the line 3-3 of Fig. 1.

of the liquid fuel in the reservoir whereby the liquid'fuel is" caused to be fed into the,

mixing 4 chamber by Vpositive .pressure which varies with the demands of the engine, the

pressure being continuous and at a maximum when the engine is standing still and gradually diminishing as the speed of the engine' increases. By a' positive pressure is meant,. in this specification, Va pressure greater than normal 'atmospheric ressure outside of the device. More particularly,

the invention contemplates means for, this purpose, including'a piston or the like, arranged to apply pressure upon the top of the liquid fuel in the reservoir and diminish said pressure as the vacuum in the engine,manifold increases in value or as the engine speeds up. The pressure whichthis piston applies to the top of the liquid'fuel' 1n the reservoir may be secured by means of tion of the spring or gravity as the case' may be, and result in a lessening of the pressure upon the liquid fuel. When the a spring element as illustrated in the draw-l ings or b means 'of the weight of the pispiston has reached the uppermost point of its travel, it uncovers a port or ports communicating with the outside atmosphere and thus establishing atmospheric pressure upon the liquid vfuel at this point. If, for any reason, the piston be further raised by any extraordinary degree of vacuum in the engine manifold, noA further lessening of the pressure on the liquid fuel will result, as the ports just mentioned are of suflicient size to insure full atmospheric pressure upon the liquid fuel.. I

The 'reasons for lapplying this additional positive pressure will now be explained:

It is well known that to secure a gaseous mixture of uniform composition, the liquid fuel component must be v.introduced into .the air component in a high state of atomization so that a rapidy and positive evaporation and volatilization can take place and a perfect gaseous mixture result. 'To secure this atomization, an atomizing nozzle m'ust be employed, such a nozzle 'consisting of an inner liquid fuel duct andan oute'r surrounding center air duct With an adjustable perforated cap at the delivery end thereof. F urther, the liquid fuel must be subjected to an air pressure so as to be fed forcibly through the fuel duct and meet the surroundlng current ,of air 'under pressure, at

the aperture/in the cap. It is to secure this atomizing effect that this additional positive pressure 1s applied to the liquid fuel in'the reservoir so that the liquid fuel is fed into the mixing chambe'r in a high state of atomization instead of in a continuous stream or intermittent slugs as is the case in all suction-operative devices. o

It is further a Well-established, thou h little known fact, that gases do not obey't ie same law of efliux as liquids so that anair flow and a gasolene flow induced by common vacuum cannot be madeto maintain any fixed ratio because with an increase in vacuum, a greater liquid 'flow proportionately will result than air flow. Consequently,- any fixed or ideal ratio between the two is at once destroyed. Therefore, it is proposed to make the liquid flow subject to,

a dlfi'erent pressure from that inducingthe air flow and tom make this difference in the two pressures exactly equal at all times to that required to maintainthe two flows at a fixed or ideal ratio.` This point 'will be hereinafter more fully ex lained. I

' The applicant is aware t at attempts have heretofore been made to subject the liquid fuel feed to pressure, this pressure being supplied from an air pump or some equiV-,-

alent 'element directly into the fuel reservoir but it is manifest that no such arrangement can secure the necessary control as is ioutlined in the paragraph just preceding.`

So far as the applicant 1s aware, no devicehas heretofore subjected theliqulld [fuel in the liquid fuel reservoir to a variable pressure which is 'made to follow a predetermined law of variation'and no device has heretofore employed an independent pressureupon the liquid fuel which will be just suflicient to give a feed of Constant q proportions to the air current under all conditions of operation.

In the drawings, I have illustrated a preferred embodiment of the invention and the particular construction`v shown comprises a casing, 1, with a central longitudinally extending chamber, 2, constituting ber, 7, has one or more outlet ports, 8, leadi ingl directly into the engine manifold 8; In

tegral with the top wall of cap, 7, are two concentric ribs 10, identical` wlth similar j ribs 12, on piston, 13, the two sets of ribs serving as top and bottom seats for spring -member, 11, which bears directly upon piston 13, and whose pressure thereon is regulated by screwing down' cap member 7, upon" the shell, 5. The annular piston 13, has channels, 14, cut in its inner and outer faces for the reception of suitable packing therein Vso as to form a fluid-tight joint between the piston, 13, and the walls 4 and 5, of the casing 1. O ne or more ports, 16, are provided in outer wall, 5, of casing, 1, and positioned so as to be uncovered by piston, 13, when.

said piston has been raised the full extent of its normal travel. This is for the purpose of admitting' atmospheric pressure to the surface of 'the liquid fuel which lis con'- tainedin chamber, 3, and-which' stands at the normal level indicated by the dotted line in Fig. 1.

Rotatably fitting the interior of shell,, 4, is a hollow ,cylindrical valve member, 17, having an enlarged conical portion, 18, fitting within the flared conical portion of the casing 1. Below the conical portion, 18, is a cylindrical neck, 19, in the side walls of which are 'cut a` plurality of apertures or ports, 20, which are adapted to register upon a suitable rotation of valve member, 17 with correspondingv apertures or ports, 21, in the stationary annular flange depending from the bottom wall 6,v from the casing 1.

The valve member, 17, is lprovided with a suitable opening or openings 8' in its side wall at the upper part thereof and the member has a closed upper end from which projects a stem, 58, that is suitably threaded for 40 tube, 25. The' position o arin, 31, is ad-4 tube, 25, is an air conduit.

v tends beyond theend of the tube, 25, so as to a portion of its length for the reception of a nut, 59, and a lock nut, 60. The end of the stem, 58, is left unthreaded for attachment of the Operating handle, 61. The lower end of valve member, 17, is closed by means of a screw-threaded ca 37, and suitable packing ring, 38. At the ]unction between the cylindrical neck, 19, and-the co'nical porti'on, 18, of the valve member, 17 a channel of semicircular cross-section, 22, is cut in the outside' face of valve member, 17. This channel is adapted to register with a similar, channeled groove 22' in the interior surface of the depending flange, 6', the two channels forming a continuous conduit around the periphery of valvemember, 17, at the junction of parts, 18 and 19, thereof. Leading from the channel, 22, are a plurality of upward inclined ducts, 23, that are 'bored in' the wall of the conical portion, 18.' vThese ducts, 23, connect with nozzles, 24, by means 'of ports, 29, on the side thereof, (see Fig. 6).

'The conduit formed by channels, 22 and 22a,

are in connection with a conduit, 46, provided in an offset from the casing', 1, to be 'hereinafter referred to. The nozzle, 24, consists of an outer tube, 25,'and an inner tube, 26, spaced within and concent-ric with the outer tube, 25, and held in rigid relation therewith by suitable spider f connections. This tube, 26, is a liquid fuel 'conduit and Tube, 26, ex-

be brought into juxtaposition with the aperf ture, 28, in the screw-threadedtc'a 27, at-

tached to tube, 25. The preciselre ative position of port, 28, with the end of'itube, 26, is determined by the position of the lever, 31, rigidly attached to cap, 27, because of the 'screw threaded relationshi of cap, 27 and justed by means of the disk, 33, attached to the Operating stem, 34,. which carries at' its .4-5 lower end a knurled:head," '35. The disk,

33, has a plurality .of slots, '32, therein, as shown in Fig. 5, for the reception of the plurality of. lever'arms, 31,,which are attached to caps, 27, and thel disk, L33, is se-` cured in any desired position by a lock nut 36, on the stem, 35, said stem being screwthreaded through cap, 37. It is thus seen that by this arra'ngement of parts,the spray nozzles,, 24, are readily and easily adjusted by loosening the lock-nut, 36, and turning,

the knurled head, 35, 'in either direction the desired amount and then tightening lock;

nut, 36. This is for the purpose of adj u'sting the spray which issues from nozzles, 24, as in' anordinary atomizer. .The nozzles, 24, "are secured -1n positlon by' lthe screw-thread on the lower end of tube, 25, which engages similar threads in the wall of member, 17.

The flow of liquid fuel through each of the atomizing nozzles, 24, is Controlled by a slotted port, 30, four of` which are shown in this device in Fig. 3, although a greater or less number of such ports and nozzles could obviously be used without departing from the spirit of this invention. The slotted ports, 30, are, for convenience, designated, 30, 30, 30, and 30d, in Fig. 3 and it is noted that the Vertical dimensions of these ports,

30, are the same and just'equal to the verti-` cal cross-section of the oil tube, 26, (see Fig.

6), but that the horizontal dimension 'of these slotted ports 30, increase in an arithmetical progression in a. counter-clockwise direction as shown in Fig. 3, that ls to say,

the horizontal diameter of port, 30', is just 26', being one-half as long as the horizontal diameter of 'each corresponding port, 30. The purpose of these beveled channels, 26', is to providea gradual-cut-of of the oil fl'ow through each nozzle as the valve member,

17, is rotated in a clockwise direction, as indicated in Fig. 3. As will seen from this figure, if the valve member, 17 be rotated a slight. distancev in a clockwise direction, the oil tube, 26, of the nozzle opposite port,

30,will pass out of register with that port,

leaving as a means of connection, the beveled lchannel, v26", which has a varying depth, the greatest dimension of which is at its point of junction with the oil tube, 26,

and slightly less than the diameter of said tube and diminishing to zero in the horizontal distance specified above. In this position of valve member, 17 i'twill be seen that a decrease flow of liquid fuel will take, place -through the nozzle opposite port, 30al 'and due to the larger dimensions of the other ports, 30, full flow is still maintained therethrough. A further'rotation of member, 17,

results'in a-complete cuttingpfl'of vthe nozzle' opposite port, 303 at which point,'the

left-hand edge of nozzle, oppositeOb-is just.- colncident with the left-hand edge of .thatport. 'Afurther rotation of. valve member, 17 will now result in a similar gradual cutting out of 'a nozzle opposite port, 30, as i that described for the ``nozrle opposite 30';

In this manner it is seen that a continuous v rotation of the valve member, 17 will finally result in the complete cutting off` of all of the nozzles i'n turn. This will require rotaangle of about forty-five (45v) degrees.

ttion of the valve member, 17. throughian i' i are similarly designated 20a, 20', 20, and 20'1, in a eounter-clockwise direction so as to show their correspondingrelation to the oil ports, 30. It will be noted that the ports 21, with which the ports, 20, eoperate, are all of the same size and equal to an angular opening o f about forty-five (45) degrees,

' whereas, the ports 20 have a common vertical dimension but increaseI in horizontal direction in arithmetical Aprogression. in a counter-clockwise direction as shown in Fig; 2. In this connection, it is noted that port,

. 204, is 'exactly equal to one of the ports, 21, w or 'has a value of angular opening of about forty-five (45) degrees'. Port, 20, is threefourths of the size of d, '20 is one-half the size of d and 20 is'one-fourth the size of (11. It is thus seen that by this arrangement a gradual cut-ofl' fof 'the air flow through these ports is seeured by means of rotation of valve member, 17, 'in a elockwise direction exaotly similar to that described for the oil ports, 30. In other words, a

fixed relationship is established between the area of oil ports and air ports in register and this ratio remains eonstant throughout the opening or elosing of the valves. The

liquid fuel flow into the chamber 3, is regulated by a plug valve, 41, rotatably mounted in a lug off-set from the easing, 1. This plug valve, 41, has two channels there-l through; a small channel, 43, adapted to register with oil supply pipe, 47, and an inlet duet, 44, when in open position and to shut ofi' connection between 47 and 44 vwhen in a closed position, and 'a larger channel' 45, which 'establishes connection between air supply pipe, 48, and conduit, 46, when lin' open position and to interrupt connection therebetween when in closed position. Plug valve, 41, is rotated to open and close its .ports by means of a lever-arm, 40, attached to a hollow metallic float, 39. The level of the' oil in chamber, 3, is maintained at a .height in'dicated by the dotted line in Fig. The arm, 40, is screwed into the plug, 41, and operates in a slot, 42, in the easing, 1, and it 'is noted that 'by this arrangement, the

air and oil feeds are simultaneously con-- trolled by a single valvemember. The oill at some'point to the pipe, 50, to indicate to the operator the pressure at any time'in the main fuel tank, 49.

'alines with t Fig. 9 shows an index pointer, 62 secured by means of screws, 63,, to the wall of the easing, 1, said pointer having a beveled straight-edge, 64, to aline with index lines, 68, seratched'in the face of index strip, 65, which is secured to the lower outer periphery of cap, 7, inan adjustable position by means of elongated slots, 66, and screws, 67 The graduations, 68, on this index are in pounds and tenths of air to one of oil so that the normal or mid-reading is 1:15 and the extreme left reading 1:14 and the extreme right readingl1:16. The graduation which e beveled edge of 62 indieates the ratlo, by weight, o f liquid fuel to air at that particular setting of the cap. For normal conditions, using a good grade of gasolene .of .70 specific gravity, this index pointer would be set atnormal or 1 :15. If now, a lower ade of fuel is used having a higher Spec' c gravity and requiring a greater amount ofair for its complete combustion, the cap would be given a slight rotation to the left, thereby bringing thepointer, 62, to some intermediate point as'for instance 1/15.2.

The operation of the device is vas follows:

'c With the engine at rest, and' the valve member 17, in a position one-eighth turn in a clock-Wise direction, from that shown on Figs. 2 and 3 in a counter-clockwise direction so as to Just slightly open air port, 20d, and oil port, 30a, and the engine turned over. This results in an operation of the pump, 51, thereby bringing pressure on the oil' in tank, 49, and at 'the same time establishing a flow of air' through supply pipe, 48, restricting channel, 45, conduit, 46, duet, 23, and nozzle, 24. At the same time, the piston 13, is in the position shown in Fig. 1, which is4 its lowermost position. The sli ht vaeuum created in the chamber above t e piston, 13, causes the said piston to be slightly raised against the compression of the spring, due to the compressed condition of the, air between the underside of piston, 13, and the liquid fuel,

vbut such movement is very slight at this initial stage, and consequently, the liquid fuel is under. a pressure almost equal to the full force of the spring. This causes an energetic emission of the oil through tube, 26, of the only nozzle in register, and this oil emithandle, 61, is moved slightly i ting from tube, 26, meets at a point just inr side the aperture, 28, with a surrounding' column of air 'under pressure whose source I have just indicated. This results in an ejection ofthe liquid fuel froml the nozzle, 27, in a fine 'spray or in a high state of atomization'. This spray combines with the air 'column entering through port, 20, is thoroughly mixed' therewith in chamber 2, and carried up and through ports, 8', in

member, 17, and out through outlet ports,

8, directly into the engine manifold, 8. As

the speed of the engine increases, the vacuum in the intake manifold is increased and this action on the top of piston, 13, causes it to be further retracted against the tension of a portion lofthe spring 11, which in turn causes a lessening of the air pressure on the 11, will now be explained:

As was stated at the beginning of this specification, it is a well established though little known fact that gases, such as air, do

not follow the same law of efllux as liquids,

` such as gasolene, and consequently for any given degree of difference of internal and' external air pressures, which difference will hereafter be referred to as effective ressure', a. less weight of air per second will ow than gasolene,.therefore, any device` wherein the air flow and liquid fuel flow is induced and controlled by one and the same effective pressure, cannot maintain any fixed ratio of flow between these two elements for varying degrees of effective ressure. of affairs is well illhstrated by the curves in Fig. 8 of the drawings', and forming partof this specification. The equation for the construction of these curves is given on the chart Fig. 8 of the drawings and the nomenclature is that adopted by Church in his M echemcs of Engneem'ng, Part II, Chapter VIII,

on the Kinetics of gaseous fluids, wherein- P1i-ist he external atmospheric air pres- Sure.

Pfrit-is the absolute pressure revailing in the mixing chamber of the car ureter, here taken to be equal to that in the intake manifold, since the two are in communication and have free and unrestricted connection.

1 'm is the weight of one cubic foot of air at the pressure and temperature of the atmosphere.

ym. is the weight of a cubic foot of'air at the pressure and temperature prevailing in the mixing chamber, here taken at thirty (30) degrees Fahrenheit, lower than that of the outside temperature.

p. is the combined coeflicient of eflluxV for adiabatic flow and varies with the effective pressure according to the table of values given in paragraph 555 of Church7s Mecham'es of Engineering, for d=.8". is the rate of fluid flow in lbs. er sec.

W is the combined coe cient of efliux corresponding to 9:.97 and 0:.6, and is effective pressure.

This condition constant. is the coeificient of Velocity and c the coeflicient of contraction of the liquid jet and these quantities, for the same liquid and under conditions of uniform flow, are sensibly constant,'so that ue is sensibly constant. Fm is the area lof the air intake oits here equal to one-half square inch for alfthrottle opening.

w is the ratlo of internal and external pressure, Pm/Pn, expressed as a percentage.

With the quantities thus defined, curve No. 1 shows the Variation in weight of liquid flow per second for varying values of w or This 4curve shows the true condition for liquid fuelflow for any condition of vacuum' existing in the mixing chamber from full atmospheric pressure down to seven pounds per square inch absolute. The scale of abscis's for liquid flow is here taken as- 1/15 of that for gaseous flow so that a single curve will give true readings on each scale'for an ideal mixture of 1:15

Curve No. 1 is constructed from equation No. 1, which is known as the so-called water formula, and is true for liquids only.

of or effective pressure; This curve lis true for air or any gas lbut not true forV` liquids. The difference in 'abscissae between these two curves shows la discrepanc tween' the actual flow of air-(curve NX). 2) and the supposed flow of air (curve No. 1) when it is assumed to follow the law 'of liquid flow as lin all suction-operativel devices. It is seen that this discrepancy of flow increases uniformly from the value of zero at a point of no effective pressure. to. a value of c-b equal to ;026 pound per second at a point where the effective pressure is 7 .7 pounds per square inch or where the internal pressufe is 7.- pounds per square inch absolute..

Thus we see that the flow of air at this effective pressure should be .148 for an ideal mixture of 1: 15 where, as a matter of fact, it is only .12'2'at this pressure while the liquid flow is .0986, making the ratio a little over 1:12.- This will show to'what extent a single vacuum controlling the two flows fails to maintain the' fixed ideal ratio sects the true aircurve at a point g, where the value of w is 90 and the internal pressure 13.2 poun'ds absolute which corre-v sponds to 350 to 100 R. P. M. of a standard four-cylinder engine. It is clearly seen that 'the liquid fuel flow following curve g-h intersects the curve a-c in but malV high speed as is shown by the abscissae ch, resulting ina waste of liquid fuel throughout all ranges 'of speed between points g and h and at the same time, `a starting mixture slightly too lean. It is readily seen that such an operation' is entirely unsatisfactory.. Another expedient, herein called case 2, isrepresented by curve No. 3b where the needle valve controlling the liquid fuel flow is set so 'as to give an ideal ratio of 1:15 at highest normal speed (point c) which gives satisfactory operation only at this speed and a mixture too thin at all slower speeds and culminating in a mixture so weak at starting as to be nonexplosive, the discrepancy here being represented by the abscissae at point d; The

flow of liquid fuel in this case follows curve No. 3b drawniparallel tov No. 1 and ,through point c. Devices employing this means of adjustment, while more economical in operation than that described under case No. 1 and have to resort to the use of priming and strangling devices in order to get a mixture rich enough to start on. Such devices further are .diflicult of operation at the lower speeds as the mixture is seen to be too thin and any attempt to throttle down to low speed would invariably result in stalling. This arrangement is, therefore, unsatisfactory and a third expedient herein called case 3 more recent than the others just described is to set a needle valve so as to give an ideal mixture at starting (point a) and allow the mixture to increase in richness up to a certain pointas for instance, point e and then dilute the mixture by bringing into action a secondary or auxiliary air supply. This gives risel to a sudden increase in -the volume of air flow with no and one intermediate point where the horizontal line e-f crosses the curve Nol, but how far even this arrangement fails to secure an ideal mixture throughout Operating speeds is disclosed by the area af-e-Z where the mixture is too rich, wasting liquid fuel and the area l-b--f, where the mixture is too thin, failing to get full power. Consequently, such an apparatus, While being a slight improvem'ent over its predecessors, is far'from being satisfactory.

So far as the applicant is aware, all devices now on the market employ one of these three types of apparatus. The applicantls idea is now to set the fuel valve so as to give ani ideal ratio at highest` normal speed (point o) as in case 2, and then to subject the liquid fuel to a progressively increasing positive pressure soas to raise the effective pressure controlling the liquid fuel feed by an amount represented by the ordinates between curves No. 8B, and No. 2, so as to place the curve of actual liquid'feed 3b, upon the curve of actual air feed No. 2, throughout its entire length, thus glving an ideal mixture at all Operating speeds.

ln this device this result is obtained by subjecting the fuel feed to atmospheric pressure at highestv Operating speed (point c) vand then gradually increasing the pressure on the liquid fuel reservoir by means of the spring, 11, represented by the ordinate d--a, equal to approximately 1.9- pounds per square inch greater than atmospheric pressure.

Since the Variation of positive pressure to be applied by the spring to the liquid fuel is not strictly linear, as is shown by the rate ofincrease of the ordinates between curves No. 2 and No. 3b, from a point 'o to the ordinate af-(Z, the upper two or three turns of the spring, 11, would be given a temper suflicient to apply the slightly greater resistance necessary to obtain the exact Variation required by the curves. The advantage of this apparatus is obvious as it gives an ideal mixture at all Operating speeds. The exact'adjustment of spring, 11, can be made from performance test by accurately setting the position of cap, 7, on casing, 1, and then securing it in the deslred posltion by set. screw, 9. The adjustment of the spray nozzle is readily made by turning the knurled head, 35, and securing the desired setting by locknut, 37. The further advantage that this present a aparatus obtains is the ability to handle liquid fuels of higher specific gravity due to the positive pressure feed and atomizing nozzles. A further advantage of a-close regulation of the height of fuel in the reservoir and the elimination of a chattering float needle valve by the use of a rotary plug cut-off valve which regulates not only the main supply tank.

. itl ``can .be 1 placed 'o maaaoo nozzles, 24.

The diameter of pipe, 50, is made larger than that of 48, so that, notwithstanding the diseharge of air through 48, pump, 51, will be able to niaintain a positive pressure of at least two pounds per square inch in the This, it is noted -is slightly in excess of the maximum pressure which the spring andl piston, 13,' Can exert on the liquid fuel in the reservoir and Consequently, the feed is niaintained'atall. times into the reservoir so long as the cut -ofl' valve, 41, allows communication; When the engineis run'aslowly 'and the volume of air delivered'by the pump, 51, is necessarily reduced, the plug member, 41, will be rotated lby -the tendency of the fuel level to rise'so as to restrict the passage of air through the pipe, 48, and channel, 46. 'By takingthe supply ,of air for the nozzle from themain,

fuel tank, use will be made of whatever evaporation'ztakes place therein, 'which evapora-v tion is now. lost through` ve nt 'holesrrequired to be left .openin gravity supply tanks. 1;` 'A furt-her advantage'of'this pressure feed' is that itenables the Carbureterfto be placed -V in.f anyj positionvdes'ir'ed` with' reference to; the' engine and j'siipply V tank, co'n's'equently,

` irectly--between the two branches of theintake-manifold andlon a level, with; the int'ake 'ports so that a very small length of .passage is traversed by the mixture'after it leaves the Carbureter and before it'enters into the Cylinders of' the motor. This is a very desirable feature as it eliminates a large part of the condensation ,of the gasolene wliich now takes place in the long leads that are necessary for carbureters so positioned as to be fed by gravity from the 'main supply system.

It will be further noted that the opening of 'the air intake ports, 20 'and 21, is effected siiiiultaneously with a correspondingly proportioned 'opening of the liquid fuel ports so that' the ratio of air to liquid lfuel supplied is maintained Constant througliout all the degrees of opening'of the ports from minimum to maximum. I desireit to be understood that in the foregoing specification as well as in the appended claims the word *maintain is used in its strictcst Sense, such as equivalent of holding or preser'ving in any particular state or condition.

'Since the complete control of the mixture is afi'ected by means of the ports, 20 and 21, no butterfly throttle. valve is necessary or contemplated for use in connection with the device illustrated in the drawings, as will appeal to those skilled in .the art and falling within the scope of the appended Claims may be made without departing from the broad prineiples of the invention.

What I- Claim isz- 1. In a Carbureter, a mixing hChamber, an atomizing nozzle, an air supply and a liquid fuel supply thereto, and pressure means for regulatin the liquid fuel supply soas to make sai liquid fuelsupply always bear a Constant ratioto said air supply.

2; In a Carbureter,.a mixi-ng Chamber, an air supply and liquid fuel supply thereto, an automatic pressure means for regulating the liquid ,fuel supply so as to make said liquid fuel supply always bear' a- Constant ratio 'by weight to said air supply.

3. 'In a Carbureter, a mixing Chamber, .an air supply and liquid fuel supply thereto,

and means to apply such a variable pressure tothe liquid fuel supply, as to make said liquid fuel supply enter said mixingchainbei' always in Constant ratio by weight to said air supply.

,4. In a carbureter, a inixing chamber, an

airsupply, and liquid fuel supply thereinto,

and means to niaintain such a pressure upon .the liquid fuel supply as to always force said 'liquid fuel supply into said mixing Chamberin Constant proportion by weight to said air supply entering therein.

5. In a Carbureter, a iixing chamber, an air supply, and liquid fuel supply thereto, and .means for inaintaining a variable pressure greater thaii atmospheric upon said liquid fuel supply so as to force said liquid fuel 'supply into said inixing Chamber always in Constant proper-tion by weight to said air supply entering therein. q

6. In a cai'bureter, a mixing chamber, an air supply thereto` and nieans for supplying liquid fuel thereto under such a variable pressure greater than atinospheric as will always niaintain a Constant ratio by weight between the rates ofv flow of said air and liqiid fuel Supplies.

In a carbureter, a niixingcliamber, and means for feeding liquid fuel thereinto, at a rate which Varies in accordance witli the law of adi'abatic gaseous flow.

8. In a earburetei', a inixing chamber, a liquid fuel reservoir in coininunication therewith, 'and'means for maintaining upon the liquid fuel in said reservoii' such a variable pressure as will force said liquid fuel into said mixing Chamber at a rate of flow which varies in aCCordanCe with the l-aw of'adiabatic gaseous efliux.

9. In a carbureter, a mix'ing chamber, and means for feeding liquid fuel thei'e'into under pressure greater than atinospheric, at a rate which varies in accordance with the law of gaseous flow.

10. In a carbureter, a mixing Chamber,

. determined Variation of fiow.

12. In a carbureter, a liquid. fuel reservoir, means to .maintain liquid fuel therein at a substantially Constant level, an atomizing nozzle, means for supplying liquid fuel from said reservoir under a variable 'effective pressure greater than atmospheric to said nozzle. q

13. In a carbureter, a liquid fuel reservoir, means to maintain liquid fuel therein vat a substantially Constant level, an atomizing nozzle, means for supplying liquid fuel and airiunder a variable effective pressure greater than atinospheric to said nozzle.

14. In a carbureter, a liquid fuel reservoir, 'means to maintain li uid fuel therein at a substantially Constant evel, an atomizing nozzle, means for supplying liquid fuel and 'air under a variable pressure greater than atmospheric to said nozzle, and means for automatically controlling said liquid' fuel and' air Supplies. I

15. In a carbureter, an atomizing nozzle, means for supplying liquid fuel and air under avariable pressure to said'nozzle and a single means ford automatically Controlling said li uid fuel and air Supplies.

16. lln a carbureter, a mixing Chamber, a fuel feeding nozzle associated vwith the mixing Chamber, means for supplying liquid fuel under pressure to the fuel feeding nozzle, means for supplyin vair under pressure to the fuel feeding nozz e, and an automatic means for regulating the air supply and an automatic means for regulating the fuel sup ly to the fuel feeding nozzle.

li In a carbureter, a mixing Chamber, a fuel feeding nozzle associated with the mixing Chamber, means for supplying liquid fuel under pressure to the fuel feeding nozzle, means for supplying air under ressure to the fuel feeding nozzle, an an automatic pressure means for regulating the liquid fuel supply to the nozzle.

18. In a carbureter, a mixing Chamber, a

fuel feeding nozzle vassociated with the mixing Chamber, means for supplying liquid fuel under pressure to the fuel feeding nozzle, means for supplying air under pressure to the fuel feeding nozzle, and an automatic means for regulating and proportionately Varying the air supply and an ,automatic means for controlling the liquid fuel sup ly. 19. In a carbureter, an atomizing nozzf, liquid 'fuel reservoir, a liquid fuel supply tank, means for supplying air under pressure to said tank, means' for Conducting air and liquid fuel from said tank to said nozzle, and automatic meansfor regulating the Supplies of air to said nozzle and liquid fuel to said reservoir.

20. In a carbureter, a mixin Chamber, a 'liquid fuel reservoir, a liquid fuel supply tank, means for supplying liquid fuel and air lunder pressure to said tank, means for lconducting liquid fuel from said tank to said reservoir, means for conducting air from said tank to said mixing Chamber, and a single means for automatically i'egulating said liquid fuel and air Supplies to said inixing Chamber.

21. In a carbureter, a niixing Chamber, a

liquid fuel reservoir, a fuel feeding nozzle l associated with the mixing Chamber, means for maintaining a positive pressure upon the liquid fuel therein and for varying the pressure inversely as the Vacuum in the mixing Chamber, means for supplying liquid fuel under pressure to the liquid fuel reservoir, means for supplying air under pressure to the fuel feeding nozzle, a float in the reserlvoir, and -valve mechanism for regulating the supply of liquid fuel to the reservoir and the vsupply of air to the fuel feeding nozzle, said valve mechanis'm being Controlled by the float.

22. In a carbureter, a liquid fuel reservoir, means for-supplying liquid fuel under pressure to the reservoir including a con-v duit, means for supplying air under pressure to the fuel feedin nozzle including a conduit, a float in the iquid fuel reservoir, and a single valve device for regulating the liquid fuel supply through the liquid fuel,

conduit, and the air supply through the air conduit, said valve' device being Controlled by the float.

24. In a carbureter, a mixing Chamber, a fuel feeding nozzle associated with the mixing Chamber and Comprising an outer air jet pipe and an inner liquid fuel tube, means for supplying air under pressure to the air jet pipe, and automatic means for supplying liquid fuel under a variable pressure greater than atniospheric to the liquid fuel tube.

25. In a carbureter, a mixing Chamber, a

fuel feeding nozzle associated with the mixpipe and an inner liquid fuel tube, means for supplying air under pressure to the air jet pipe, means for supplying liquidvfuel to the iquid fuel tube, and an automatic valve means for regulating and roportionately varying the supply of air an liquid fuel to the nozzle.

26. In a carbureter, a mixing chamber, a liquid fuel reservoir, a liquid fuel feeding nozzle associated With the mixing Chamber, and comprising an outer jet pipe and an inner liquid fuel tube, means for supplying air under pressure to the air jet pipe, means for supplying liquid fuel under pressure to the liquid fuel tube, a float in the liquid fuel reservoir, and a single valve memberfor regulating the supply of air and liquid fuel to the nozzle, said valve member bemg controlled by the float in the reservoir. A

27. In a carbureter,,a mixing chamber, a liquid fuel reservoir, a liquid fuel feeding nozzle associated with the mixing chamber, and comprising an outer air pipe and an inner liquid fuel tube, means for supplying air under pressure to the air pipe, means for supplying liquid fuel under pressure to the inner fuel tube, a floatin the liquid fuel reservoir, and a single-rotary valve' member for regulating the supply of air and liquid fuel to the nozzle, sai rotary valve member being operatively connected with the float.

ing liquid fuel to the liquid fuel tu s,

means for supplying air under pressure to the air pipes, and means for simultaneously adjusting the caps of the air pipes.

29. In a carbureter, a mixing chamber, a plurality of fuel feeding nozzles associated with the mixing chamber, each fuel feeding nozzle comprising an vouter air pipe and an inner liquid fuel tube, and an adjustable cap member for the air pipe, meansfor supjlying liquid fuel to the liquid fuel tu es, means for supplying air under pressure to the air pipes, means for siniultaneously adjusting the caps of the air pipes, said means comprising a stem mounted for rotation, a connection between said stem and each of the caps of the air pipes, and means for looking the stem in adjusted position.

30. In a carbureter, a mixing Chamber, a plurality of fuel feeding nozzles associated with the mixing Chamber, each fuel feeding nozzle comprising an outer air jet pipe, an.

tubes, means for supplying air under pressure to the air jet pipes, means for simultaneously adjusting the caps of all of the air jet pipes, said means including a rotary stein, a head ,on the stem, and an arm on each of the caps of the air jet pipes operativ'ely connected With said head.

31. In a carbureter, a mixing chamber, having an air inlet and mixture outlet, a liquid fuel reservoir, means for maintaining liquid fuel therein at a substantially constant level, and means for'maintaining a positive pressure upon the liquid fuel in the reservoir,

said means including aiston element in the' to app y pressure upon the reservoir actin liquid fuel, said liquid vfuel reservoir having communication above the piston element with the mixture outlet, the piston element being subject to the influence of the difl"erence in air pressures existin in said mixing chamber and voutside atmosp ere.

32. In a carbureter,' a mixing chamber having an air inlet and mixture outlet, a liquid fuel reservoir, means for maintaining liquid fuel therein at a substantially Constant level, and means for maintaining a positive pressure upon the liquid fuel in the reservoir, said means including a' piston element in the reservoir, a spring acting uponthe piston to apply pressure upon the liquid fuel in the reservoir, the liquid fuel reservoir having a communication above the iston with the mixture outlet, the piston ing subject to the influence o'f the difference in air pressures existing in said mixin Chamber 'and outside atmosphere.

33. n a carbureter, a mixing chamber having an air inlet and mixture outlet, a liquid fuel reservoir, means for maintaining liquid fuel therein at substantially constant level, and means for 'maintaining a positive pressure upon the liquid fuelin the reservoir, said means including a piston in the reservoir acting to apply ressure upon the liquid fuel, and ports in t e liquid fuel reservoir controlled bv the piston to estab-. lish atmospheric pressure upon the liquid fuel in the reservoir.

34. In a carbureter, a mixing chamber having an air inlet and mixture outlet, a liquid fuel reservoir, means for' maintaining lliquid fuel therein at a substantially Constant level, and means for maintaining a` positive pressure upon the liquid fuel in the reservoir, said means including a piston in the reservoir, and a spring acting upon the piston to applv pressure upon the liquid fuel in the reservoir, the liquid fuel reservoir having communication above the said piston With the mixture outlet, the piston being subject to the influence of the difference in air pressures existing in said mixing chamber and outside atmosphere, and ports in the liquid fuel reservoir arranged to be uncovered by the piston to establish atmospheric pressure upon the liquid fuel in the reservoir.

35. In a carbureter, a liquid fuel reservoir, means for maintaining liquid fuel therein ,at a substantially Constant level, and means for maintaining positive pressure upon the liquid fuel inthe reservoir, said means including an adjustable Cap member for the reservoir, a piston element in the reservoir, and a spring interposed between the said Cap and the piston, and acting upon the piston to apply pressure upon the liquid fuel in the reservoir.

36. In a Carbureter, a liquid fuel reservoir, means for maintaining liquid fuel therein at a substantially Constant level, and means for maintaining positive pressure upon the liquid fuel in the reservoir, said means including an adjustable Cap member for the reservoir, a piston element in the reservoir, and a spring interposed between the said Cap and the piston, and acting upon the piston to apply pressure upon the liquid fuel in the reservolr, and means for locking the Cap in adjusted position.

87. In a Carbureter, a mixing Chamber, a liquid fuel reservoir in Communication therewith, means for maintaining liquid fuel in said reservoir at a Constant level, means for maintaining a pressure greater than atmospheric upon said liquid fuel to force' said liquid fuel into said mixing Chamber.

'38. In a Carbureter, a mixing Chamber, a liquid fuel reservoir in Communication therewith, means for maintaining liquid fuel in said reservoir at a Constant level, a piston element and a spring aCting upon a piston element to maintain pressure upon said liquid fuel to force it into said mixing Chamber.

39. In a Carbureter, a mixing Chamber, a liquid fuel reservoir in Communication therewlth, means for maintainingl liquid fuel in said reservoir at a Constant level, a piston element and a spring acting upon the piston element to maintain pressure upon said liquid fuel to force it into said mixing Chamber, and means for adjusting the tension' of the spring.

40. In a Carbureter, a mixing Chamber, a liquid fuel reservoir in Communication therewith, means for maintaining liquid fuel in said reservoir at a Constant level and means for maintaining a pressure greater than atmospheric upon said liquid fuel to Aforce it into the mixing Chamber, and means for varying the pressure upon the liquid fuel directly as the pressure in the mixing Chamber.

41. In a Carbureter, a mixing Chamber, a

.liquid fuel reservoir in Communication therewith, means for maintaining liquid fuel in said reservoir at a Constant level, means for maintaining a positive pressure upon said liquid fuel to force it into the mixmg Chamber'and for varying the pressureupon said liquid fuel directly as the pressure 111 the mixing Chamber, said means inCluding a piston element. 4

42. In a Carbureter, a mixing Chamber, a liquid fuel reservoir in Communication therewith, means for maintaining liquid in said reservoir at a Constant level, means for maintaining a positive pressure upon said liquid fuel to force same into the mixing Chamber, and means for varying the' pressure upon said liquid fuel directly as the pressure in the mixing Chamber,sa1d means including a piston elementand a sprlng upon the piston element to apply pressure upon the liquid fuel.

43. In a Carbureter, a mixing Chamber, a liquid fuelv reservoir in Communication therewith, means for maintaining liquid fuel in said reservoir at a Constant level, means for maintaining pressure upon the liquid fuel in the reservoir, said latter means being subject to the influence of the difference of air pressure existing in the mixing Chamber and the outside atmosphere.

44. In a Carbureter, a mixing Chamber, a liquid fuel reservoir in Communication therewith, means for maintaining liquid fuel in said reservoir at a Constant level, means for maintaining pressure upon the liquid fuel in the reservoir to force said fuel into the mixing Chamber, said latter means in- Cluding a piston element subject to the infiuenCe of the difference 'between the air pres' sure existing in the mixing Chamber and the outside atmosphere.

45. In a Carbureter, a mixing Chamber, a liquid fuel reservoir in communication therewith, means for maintaining liquid fuel 1n said reservoir ata Constant level, means for maintaining pressure upon the liquid fuel in said reservoir to force the liquid fuel into the mixing Chamber, said means including a plston element and spring acting upon the piston to apply pressure upon the liquid fuel, said piston being subject to the difference between the air pressure existing in the mixing Chamber and the outside atmosphere. i

46. In a Carbureter, a mixing Chamber, a

liquid fuel reservoir in communicationvv latter means including a piston element acting to applyfpressure upon the liquid fuel in thereservoir, said piston being directly Asubject to the difference in air pressure existing in said mixing Chamber and the outside atmosphere.

1,829,aoo

47. In a carbureter, a mixin chamber, a liquid fuel reservoir in communlcatlon therewith, means for maintaining liquid fuel in said reservoir at a Constantv level,

means for maintaining a positive pressure upon the liquid fuel to force said liquid fuel in the mixing Chamber and for varying the pressure upon the liquid fuel directly as the pressure in the mixing chamber, and means for establishing atmospherio pressure upon the liquid fuel when the pressure upon the liquid fuel is reduced to a predetermmed degree- V 48. A carbureter comprising, a liquid fuel reservoir with liquid fuel supply there- 15 to, anatomizing nozzle with air supply and liquid fuel supply thereto, and a single means for regulating the supply of air to said nozzle and liquid fuel supply to said reservoir.

In testimon whereof I hereunto afix my signature in t e presence of two witnesses.

AUGUSTIN M. PRENTISS.

Witnesses:

s F. C. Wm'rNnY,

A6 S. Bism. 

